Our house in FL is elevated 10’ on concrete block posts, with 2000 sq ft of 4” concrete slab under for an open carport, enclosed workshop and utility room. On Fridays at 5pm the neighborhood comes for a potluck happy hour. I’d like to tile the entire slab, but am concerned about parking our cars on the tile. Is this an OK idea? Are there certain types of tile and installation techniques to use so that tiles wont crack under the cars? Is there a better surface to apply to improve the appearance of this area for entertaining? Thanks. Mark R
Replies
You'd have to choose the type of tile and the method of installation very carefully, and even then you'd be in danger of, say, rocks caught in tire treads causing damage.
I'd suggest you look into one of the several available garage floor coating schemes, most involving an epoxy-like paint.
No problem at all. Many garages are tiled. You do have to make sure you hire a good installer who sets the tiles ina solid bed of thinset.
You also need to plan for expansion joints. Tile, particularly porcelain, expands and contracts at a different rate than concrete and the thinset will fail by shear and the tile will pop. I can see that the pad is shaded but I'm sure that at some time during the day, sunlight does hit part of it. The concrete should already have expansion cuts--but you can't tile over those cuts. If it doesn't have relief cuts I would expect that you probably have small cracks in it. You'll need to fix them with an epoxy concrete repair product--something from Sika, for example. (If it does have expansion joints, you'll have to plan your tile around those relief cuts. You may be able to fill them and make new relief cuts. Get in touch with the technical dept of Mapei, for example.) With the concrete pad fixed, you can make your cuts WHERE THE TILE GROUT LINES WILL BE. It takes a lot of planning. --Size of tile you're using and width of the grout lines, for example. Cuts have to be at exactly 90 degrees, so use a big 3/4/5 triangle to lay them out perfectly. Lay them out in chalk for the concrete cutter (or do it yourself). Be careful not to get thinset in the cracks, or you'll have to carefully get it out yourself with a diamond blade on a circular saw. Now fill these expansion joints with backer rod and then with a high quality rubber caulk. Put down masking tape and do it right, peeling away the masking tape before the caulk has dried.
I'm telling you this information based on my own knowledge from tiling a concrete pad. I put expansion joints every + - 6 feet--which was the correct spacing for my climate.
Are there low spots or high spots in the concrete pad? Remember the machines that the janitors used to use for polishing floors in your school? You can rent those machines but with grinding stones on them to take off high spots. There are leveling compounds for low spots. You'll also have to roughen up the whole pad with a diamond disk on your hand held grinder. (That machine your rent will definitely make the concrete too smooth for a good concrete/thinset bond. The top layer of concrete is weak and is composed of cement, sand and water that has floated to the top. You'll often see that it has spalled off on sidewalks and the like. You have to remove this layer and get down to aggregate to get a good bond for the thinset. The knowledge base that you need goes on and on. Google is your friend. Mapei have a whole bunch of vids and technical bulletins for that will help you. (Be glad you don't have freezing weather. It complicates the technical aspects of the whole job.)
Are you down near Everglades City? Saw houses like yours when we wintered in Naples.
Great explanation Suburbanguy! I have one addition to your recommendations: an anti-fracture/crack suppression membrane should be added to the assembly. Lots of people use Schluter but there are other manufacturers available. You thinset the membrane to the slab and then tile to the membrane as described above.
Sawdust_Steve. Those Schluter membranes aren't necessary on a concrete slab, but if a membrane is used, it might eliminate the need for expansion joints. I'd check with tech service at Schluter to be on the safe side. It's rather expensive stuff and concrete cuts are cheaper ...but yes, on a normal residential floors, I wouldn't use any other installation method.
Wanted to add, (more knowledge base) that when using these membranes, and there are several manufacturers, you must use an UNmodified thinset. What's that? It's normal thinset. "Modified thinset", on the other hand, is made by adding a white liquid latex additive. It changes the physical properties....
Modified thinset was used when I had my concrete pad tiled, but I live a climate of cold winters. Not sure it's necessary in Florida. Yes, you read that right. I've only tiled a small 3x4 foot area that was too small to have done by a pro. --I wanted to know everything I could about outdoor tiling so that I could spec the job properly. Ten years and not a single popped or cracked tile.
My garage floor was tiled back in 2003.....no issues yet (at least not with the floor). Went with a larger tile. No expansion joints.
You're correct. No need for expansion joints when the temperature remains within a narrow range. That's why I asked about sun shining on his carport slab. In my research, I saw pictures of (dark) tiling that had popped simply from sun shining through a window onto the floor.
Nice garage 363034 ! Looks like you could eat off the floor. I'd be very afraid to do any work in there.
“[Deleted]”